shares slid 6% late Monday after the company warned of another earnings shortfall.

The Pleasanton, Calif., maker of teleconferencing equipment says it expects first-quarter net income of 17 cents a share, on a so-called non-GAAP basis excluding certain costs, on about $136.5 million in sales. This is the second downward adjustment of first-quarter guidance by Polycom this year.

Analysts had been looking for a profit of 19 cents a share on $143 million in revenue for the quarter ended March 31. A year ago, the company made 13 cents a share on a pro forma basis on revenue of $119 million.

The company plans to report first-quarter earnings on April 20.

Polycom shares fell 98 cents to $15.40 in postclose trading Monday.